The Crossover
by Bluedermis
Summary: My goodness, 40k hasn't yet found the Yeerks or any remnants? Could it be a myth? Sergeant Hieronymous Strab and his squad find out it is anything but. Please note the angst is 40k angst, so more like "NO! I don't have enough shots to purge the world!"
1. The Prologue

_What the feth? Where the fethin' warp are we?_

- Sergeant Hieronymous Strab, T+19 minutes

In the fourty-first millennium, there is only war. Most of these wars, while important to the individuals concerned, have little or no effect on the galaxy as a whole. One specific war, however, was of great concern to the Imperial historians.

This war was one so far in the past as to be almost forgotten, and it was only through a series of apocryphal books, allegedly the accounts of veterans of the human side of the war, that any knowledge was at all retained. The five combatants concerned were all humans (one alien alleged to part of the group was dismissed as a primitive version of a 'deus ex machina', a way to explain certain events that were presumably only documented after the effect), and had unlocked primitive psychic powers, such that they were able to take the forms of other beings. They, using these abilities, were able to save the human race from an alien infestation known as the "Yeerks". However, one discrepancy had emerged. The xenos concerned had apparently had a large empire, such that they were unable to be truly beaten by the humans, only prevented from capturing Holy Terra. Strangely, when records of the truly ancient xenos known as Eldar were examined by Inquisitors of the Ordo Xenos, there was no mention of such a race ever having existed.

Some historians theorised that the accounts concerned were in fact a fictional series, as noted by the apparent single author, the same for all the accounts, despite the different characters who narrated the books. This was countered by the other popular theory which held that the 'author' was merely taking the credit for the resistance group, known as the "Animorphs" for their morphing capability, while the books were all written by the narrators in question. One far more disturbing question regarded the beings known as the Ellimist and the Crayak. These apparently god-like beings had much in common with the Chaos gods Khorne and Tzeentch. Worse still was that the humans appeared to be supporting the Tzeentch-like being.

This would have been merely a piece of trivia, almost as important as the Tanith 1st victory on Monthax, had it not been for the warp storm of 9339487.M41. While this was not a momentous warp storm for the greater universe, it did unfortunately result in the disappearance and presumed destruction of the 365th regiment of Bellis XIV, which resulted in the Imperial forces on Cadia being harder pressed during the 13th Black Crusade.

For nearly all of the eight thousand fighting men of that regiment, it was indeed the end; a failing Gellar field had allowed daemons and other warp entities to board the vessel. Only two squads survived the encounter, being able to hold out in their troop ship's armoury until the warp engine, having detected the failure of the Gellar field, finally cut out. However, while they were alive, they had not reached safety yet. The troop ship emerged from the warp virtually destroyed; all that survived was the armoury section. While it was not designed to enter the atmosphere, the surviving armour plating around this remaining section was happily large enough such that they would not burn up in the atmosphere of any planet they might enter. They still had inertia, and propelled by their momentum, the broken section of ship managed to survive passage through a battle between two battleships and a horde of fighters, and was in fact seen by one of these fighters. As this fighter was watching, another shot it in the rear section and sent it spiraling into the atmosphere, and now following this new arrival.

This is where our story begins. It is the third millennium, and there is only war.


	2. The Beginning

_Humans! Where there's one, there's a hundred of 'em!_

-Corporal Gallus Bionda, T+28 minutes

My name is Hieronymous Strab.

I'm a sergeant in the God-Emperor's Own Imperial Guard, 365th Bellis XIV Infantry Regiment. Second Company, Third Platoon, Second Squad. I am a product of the Imperium of Man, an empire that stretches the entire galaxy, an empire of a million worlds. We are beset by alien threats, betrayed from within by heretics and rebels, but for ten thousand years we have endured. Even with that long list of achievements, we are nothing before the mindless forces that beset the galaxy.

These forces were the very cause of our marooning on what we came to know was Holy Terra. In a particularly bad warp storm, the Gellar fields on our ship were defeated, and the warp entities that emerged destroyed most of our ship, and all but two squads. We are alone, and the guiding beacon of the God-Emperor does not seem to exist.

We are no weaklings, however. We are the soldiers of the God-Emperor. We shall die in His service and until that time we shall live. But if I'd know the sort of battle I was about to get into, I'd have opened the doors to the daemons and seen how many we could take with us.

The battle in question started for us about thirty standard minutes after we landed. We were (thankfully, given our condition) all intact, and while there were a few sprains and broken bones, we were all praising the God-Emperor for our safe arrival. We emerged from the armoury to find that we had landed in what seemed to be a construction site. Thankfully, this would allow our armoury to pass by unnoticed by the natives of this world. We merely had to hide and set off a distress beacon. At least, that was all we _thought_ we'd have to do. As it turned out, we were, as we got out, among about twenty five humans who saw the falling starfighter. It was clearly out of control, but not only that; it looked unlike any fighter I've seen before or after. I don't remember it clearly, but what I do know is that the closest thing I've seen to it is the desert creature called the "scorpiones" in High Gothic. Regardless, the pilot (despite being a foul xenos) was a very skillful pilot; despite the quite clear damage to the craft, he managed to land it relatively well. I scanned the surroundings to my left and right, and it was then that I saw the beings who would shape our viewpoint of the world for the next few days.

Then, their names were unknown. What I did know, though, were that these were homo sapiens sapiens, human beings, the very image of the Sacred Form of Humanity. We quickly came to the (false, as it happened) conclusion that we were somewhere in the Imperium. But one thing troubled me. The humans wore clothes that appeared to be very finely crafted, beyond the reach of the average habworker, but did not wear any of the other traditional signs of wealth such as rings, crowns, or in fact jewelry at all. Neither did they have bodyguards. Not just that, but they seemed to be approaching the alien spacecraft, not with fear or righteous anger, but with awe and, I hate to admit it, something approaching love. I held back my fury. We have all heard of the mind-twisting powers of the Eldar, and while this vehicle did not appear to be such, there was every chance this alien could be just as dangerous. If I had known just how right I was, I would have grabbed a missile launcher and destroyed it then and there. But perhaps it was better I did not.

My fears were confirmed as a pulse of psyker energy surged through our minds. If you've never had a psyker speak to you mind-to-mind, you can't possibly imagine it. It was probably different to the five people (Adolescents, actually, at this point in time) who were surrounding it, not having what I've been told is the 'basic psychic state of humanity' or some Magos Biologis gak like that. But I digress. The alien said two words.

**I know.**

Now, I know what you're probably thinking. The alien wasn't alone, and didn't even notice the humans nearby! But in fact, I learned later that the adolescents had been talking to him. Before I could really react, or even think about how _to _react, the alien had, once more, sent a pulse of psyker power out again.

**Yes. Do not be frightened.**

I started catching on at this point, and I was glad I hadn't shot the adolescents like the xenos-loving scum I had thought they were. They had been bewitched, but the alien knew they still had enough humanity to recoil at it's form. I motioned to my squad to follow me. This alien would be emerging, and the opportunity to learn its form and its plans would be invaluable. We crept over with cat-like tread. The night was filled with a sort of silent dread as the spacecraft opened itself to the world.

What came out was a form so alien it dwarfs the capacity of understanding. I recoil at the thought of it, even today. It looked like a sort of human crossed with a grox, or one of the more grotesque forms of Tyranid monstrosities, like some insane tech-priest had taken the top half of a human, chopped off the head of the grox, and sewed them together.

The squat and unwieldy form was deceptive. But that was only learned later. For now, we could not think of it as a threat but for the psychic powers it obviously had. We did not think much of stealth now, and to be brutally honest, did not pay much attention to discipline. This was our first mistake.

The second mistake came just a few moments after the first.

**Hello**. quoth the alien.

We, the pathetic fools we were then, answered it.

"Hello." quoth the fools.

It had a remarkably brutal effect on both the alien and the humans. Now, it seems appropriate to give a brief visual description of how the normal 365th Regimental Infantryman looks. We've got the traditional Imperial Guard equipment, most notably a lasgun, a flakvest, a set of fatigues, and a helmet. The fatigues were coloured by quadrants. Now, it is well known that the fatigues are made out of the most common materials available at that time. Unfortunately for our regiment, we had been formed at a time in which ochre-brown was apparently very popular among the civilian population, so the most common material was a combination of purple, white, red and yellow. This, quite unfortunately, is not at all useful in wartime for camofluage or any other useful purpose besides guiding the enemy's fire directly to your head. So we must have looked very strange, especially when you combine the strangely coloured fatigues with the fact that the combat webbing, the flakvest, and all the other parts of our equipment had been made by the local Forge World, and were in fact intended for an ochre uniform.

Now you have a basic picture of how we looked, you can imagine the effect we had. On the one hand, the alien would have probably focused on our weapons, and worked out that we were well-armed. On the other, the people would have focused on our colours, which I have since learned give an entirely different impression to the one we would like.

In fact, the alien had been so affected by our appearance that he fell out of his ship.


	3. The Warning

_I have at my command an entire battle group of the Imperial Guard. Fifty regiments, including specialized drop troops, stealthers, mechanized formations, armored companies, combat engineers and mobile artillery. Over half a million fighting men and thirty thousand tanks and artillery pieces are mine to command. Emperor show mercy to the fool that stands against me, for I shall not. _

-Warmaster Demetrius

The shock we had caused those kids wasn't as bad as the surprise we gave to the alien. At least, that's what appeared to be true, because one of those kids just leaped up to try and help it, like it was a person.

"Look!" cried another one of the kids, who I later learned was named Cassie. "He's hurt!" I could almost feel the... compassion, I think the word is, in her voice.

Made me want to throw up, I can tell you. An alien lover is more than I can stomach. But it's the same with any sane person, ain't it? You don't want one of them on your planet any more than you want a heretic, or a criminal.

**Yes.** sent the alien. **I am dying.**

Now, I don't mind telling you, I was pretty happy with the alien about to die. After all, if he wasn't going to die, I'd kill him myself, and this saved me a shot! But the kids there, they had the entirely different reaction.

"Can we help you?" asked a third kid, who goes by the name of Marco. "We can call an ambulance or something."

Ambulance... Where did that word come from... I tried to remember what the word even meant, but I thought, from the context, that it meant something like the local medicae. It meant something like it, I could remember... But it was an old word, I thought. I couldn't remember it completely.

"We can bandage that wound." Cassie said. She motioned to one of her companions, the leader of the bunch, whose name we found out quite soon. "Jake, give me your shirt. We can tear it up and make bandages."

By the Emperor, I was right furious then. Attempting to save an alien? Requesting a good, human, doctor try to heal it? I'm usually a diplomatic, balanced, calm person, but this was beyond belief. Beyond heresy, beyond xenos-loving, this was downright treason!

"How DARE you?" I shouted. "Putting the life of a filthy alien before that of a human?"

I moved closer to the girl, intending to remind her of her duty as an Imperial citizen. This was- This was spitting on the God Emperor! She was just so- just so INFURIATING! I raised my hand above my head, about to swing it down, when the alien spoke again.

**The intolerant human is right. The wound is fatal.**

"NO!" Jake cried. "You can't die. You're the first alien ever to come to Earth. You can't die!"

I was shocked. I am rather an erudite person, and so I do know a bit of the older names of important places. This name, however, was for the most important place in the universe: Holy Terra itself.

For those who don't know, Terra (or Earth) is the birthplace of the God Emperor of Mankind. He led the Great Crusade from here. He was mortally wounded here during the Horus Heresy. He was placed on the Golden Throne here. It is the centre of our faith, of our beliefs, of our religion, of our hope.

To learn that this alien scum had stepped onto this sacred ground...Well, it showed the typical arrogance of the xenos. But what was worse is that these humans obviously knew their heritage so well, and turned their backs on it! How could they imagine letting this... this scum live on their world? How could they be so... so treasonous? Were they servants of Chaos? Did they worship the daemons, even here, even on the very home of the God Emperor, just a short orbital flight from the home of the Inquisition?

Did they seek death, or were they just blinded by their 'power'? Did they think that tolerance would help them to survive? Did they not know that the rewards of tolerance were treachery and betrayal? How could they be so... so weak?

I was speechless, and the alien and the teens continued their conversation.

**I am not the first. There are many, many others.**

I don't recall much about this meeting, but what I do remember is me falling to the ground at this moment. How...HOW...HOW COULD THE XENOS HAVE GOTTEN TO EARTH, AND THERE WAS NO RESISTANCE? How? Had the people of this world fallen to heresy, to tolerance, to evil?

What had happened? Had I been sent into the past? Had the warp itself torn my brain apart, and the daemons were torturing me? How could these humans be so foolish?

I was ignorant at that stage, and well, I guess I still am, but now I know precisely why these aliens had managed to land on Terra, why humanity seemed to tolerate them, why they had not been destroyed already. But then, I could only think about logistics... We had somewhere in the range of three hundred lasgun power cells per soldier now. Each power cell would fire up to sixty shots per charge. We also had more heavy weapons, and maybe enough ammunition to destroy a small fort with them. Would we have enough to purify this land? Would we have enough to instill in these ignorant beings the true glory of the God Emperor?

How could we, just two squads of infantrymen, ever be able to destroy this army of aliens without the help of the God Emperor? We weren't Space Marines, we weren't Sisters of Battle, we weren't Kasrkin, we were just twenty dog soldiers, twenty of the Imperial Guard, where there should be thousands, millions... How could we do a thing?

I confess, that at this stage in time, I despaired. The aliens had insinuated themselves into the human world, had hidden themselves obviously well. We had nothing powerful enough to stop them...Nothing that could prevent them from obliterating the Emperor's soldiers here.

I didn't pay attention to what the teens said after that, but I do remember what the alien said next.

**Not like me. They are different. They have come to destroy you.**

I looked up, and a fell mood came upon me. The aliens were here, on Terra, here to wipe out humanity. I was nothing, but we could not stand by. These teens would serve as exemplary Whiteshields, having almost everything needed for a full squad...

Cassie was obviously a medicae in training. Jake seemed to have charisma- with the Emperor's aid, he could become a good leader. The others would find their path soon, but I already knew we could do something.

We could form a resistance movement. We could use guerrilla tactics.

We are Imperial Guardsmen. We are the Hammer of the Emperor. We will win here, or die trying.

All these thoughts passed through my head in an instant. Just in time for the xenos to repeat what he had said.


	4. The Decision

_Children you call them? They can pull a trigger just as well as veterans, and they have the spirit of a bull narthax. Call them children if you wish - I call them troops._

-Colonel Marus Cullen, Pannonia 5th Infantry Regiment on Whiteshields

**They have come to destroy you.**

This statement, while it seems terrible and impossible to the ignorant, to those who know of the Imperium of Man, it comes as no surprise.

You see, in the Imperium of Man, we've seen many different types of aliens, and all are evil, murdering, scumbags. You've got the sinister, degenerate Eldar, the berserker Orks, the insidious Tau, the mindless hordes of the Tyranids, and the machine-like Necrons. Most of my experience was with the Orks.

Now, they'll tell you that the orks are weak, that they're cowardly, that their bones are brittle and snap easily, but I can tell you this; they are nothing of the sort. They're stronger than a grown man. They'll fight for fun, and they never retreat. They are much more powerful than a human and if it was a fair fight, they'd have conquered us. If it was a fair fight.

But we humans are far more intelligent than them. We can plan, we can strategise, we can use tactics. Thats what separates us from the xenos, from the aliens. We are BETTER than them. This we know.

But the Yeerks were unlike any alien we've ever faced. Sure, the Eldar will trick you. But these Yeerks would... Well, I'll get into that later. You don't have long to wait.

**They are called Yeerks. They are different from us. Different from you, as well.**

I snorted at this statement.

"Of course they are different from us! We humans are pure, sacred. We are BETTER than you scum." I proclaimed. At this, the alien stared into my eyes, and I realised that, despite its injuries, it was still full of hate and envy. It had good reason. After all, what alien would NOT want to be human? It was jealous of my humanity.

**Many are here.** the alien told us.

This was depressing, to say the least. Many aliens here? Could they have already landed a suitable invasion force? My feelings were squarely soothed by the xenos' next statement.

**Hundreds. Maybe more.**

How could such an insignificant number pose any threat at all? I've been in battles between thousands, tens of thousands, hundreds of thousands, even millions. If the number is barely in the hundreds, how could they be any harm?

Of course, the civilians, being unexperienced in the ways of war, thought this was a large number indeed, with one of the boys, not the possible leader, but one of the other two, asking "Why hasn't anybody noticed them? I think someone would have mentioned it at school."

Suddenly it clicked.

My brain, filled with at least some basic knowledge on the pre-Imperium languages, recognised this strange one, 'school'. I knew what it meant. And I knew what that meant for us.

School, the pre-Imperium version of the Scholae. Archaic now, and only known as a curiosity.

This meant one thing.

We had travelled in time.

Don't ask me to explain the Warp, because I can't. Don't ask me to explain Warp travel, because once again, I can't. All I know is that the Warp is the home of Chaos, and like Chaos, it is unpredictable. Fast routes become slow. Time itself is changed. The best analogy, I think, is from _Space Lanes of The Imperium and the Perils of the Galaxy_, from Volume 1, chapter 1, which reads:

"_Consider, dear reader, this metaphor to explain how travelling through Warp space works; that of a fast flowing stream. The stream represents Warp space moving swiftly along its motionless banks, which represent real space. A corpse dropped into the water upstream will not move relative to the water, but is merely carried by it until it lodges at some point downstream from its original location._"

We were on Holy Terra, that was certain. When we were, however, was much less sure.

But that didn't matter.

We were humans. We would deny the alien, the mutant, the heretic.

This alien seemed to know what we were thinking, for he said

**You do not understand. Yeerks are different. They have no body, like yours or mine. They live in the bodies of other species. They are . . .**

As I've said before, nothing really prepares you for your first psyker message. This is multiplied a thousand-fold when it involves pictures. When something bursts into your brain, bypassing the conduits from the eyes, it can send even the bravest men to their knees, wetting themselves in primal terror.

These humans won my respect in that, at least.

The image that the alien had placed in my mind was different to every other alien I'd seen. It was in the form of a slug, glistening and writhing.

The image broke as one of the teens, the same one that spoke last if I remember correctly, who I now know as Marco, spoke again.

"I'm guessing that was a Yeerk." he said. "Either that, or a very big wad of slimy chewing gum."

**They are almost powerless without hosts. They -** the alien cut off, and a spurt of pain flooded through.

I guess I'm used to the feeling of psyker magic, or maybe the Emperor still protects here, but I could endure it easily.

The kids could feel it, though, and they seemed to be more affected. But I digress. This isn't really important to the story, just a bit of trivia.

**The Yeerks are parasites. They must have a host to live in. In this form they are known as Controllers. They enter the brain and are absorbed into it, taking over the host's thoughts and feelings. They try to get the host to accept them voluntarily. It is easier that way. Otherwise the host may be able to resist, at least a little.** continued the xenos.

This was pretty mindblowing, as you might guess. These other xenos could take over a human's brain? They could hide and would never be noticed. All that could prevent an epidemic would be the Inquisition, and even they might be fooled by some of them.

It would be critical to the Imperium that I, whenever this is, find a way of stopping this take over, or detecting it, and then leaving it somewhere for the future generations. Only then could I not have failed. With that information, Humanity would be safeguarded from another group of treacherous aliens. They would be unable to hide themselves.

I had my goal, at last. For better or for worse. Whether I lived or died. I knew what I would do from now on.


End file.
